A metal sphere with radius r = 1.10 cm is supported on an insulating stand at the center of a hollow, metal, spherical shell with radius r = 9.00 cm . Charge +q is put on the inner sphere and charge −q−q on the outer spherical shell. The magnitude of qq is chosen to make the potential difference between the spheres 400 VV , with the inner sphere at higher potential.

The magnitude of q = 0.612nC

Explanation:

The concept of coulomb's law was applied as it relates to the potential of each surface mentioned in the question. we are considering an inner sphere and a spherical shell each with its own radius.

The potential at each sphere was gotten, thereafter the potential differences between each sphere was equated to get the magnitude of the charge as it is shown in the attached file.

The steps and the mathematical explanation are as shown in the attachment.

it has to be b, about 97 percent.

scattering of light by tiny particles in air to produce the colors we see on sky, is dependent on the following factors:

(i) wavelength of light

(ii) size of the scattering particle  

(iii) distance traveled by light through the atmosphere.

according to rayleigh's law of scattering, the amount of scattering is inversely proportional to the fourth power of its wavelength. shorter the wavelength, greater is its scattering. hence violet/blue light is scattered more than red.

sun's light is a composite light ( visible light) with wavelengths in the range 400 nm (violet) to 700 nm (red). as sunlight passes through our atmosphere, the molecules of air scatter light according to their wavelengths. during sunrise and sunset, the sun's position is below the horizon. hence light from the sun travels a greater distance in the atmosphere when compared to its position a noon.

as sunlight enters the earth's atmosphere, blue light is scattered away and at the end of its journey in the sky, only red and orange wavelengths remain in the beam.

hence at sunrise and sunset, the sky appears reddish orange.